Heart attack survivors who step up their exercise efforts may live longer than those who remain inactive, a Swedish study suggests.Compared to patients who were inactive for the first 10 to 12 months after their heart attack, patients who were active during that whole time were 71% less likely to die during the four-year study, researchers reported in the Journal of the American Heart Association.People who were inactive at first but who increased their activity levels over time, meanwhile, were 59% less likely to die during the study than their constantly sedentary counterparts, and even people who reduced their activity levels but still got at least a little exercise were 44% less likely to die.Overall, the study involved 22,227 patients who were surveyed twice about their activity levels: at 6 to 10 weeks after a heart attack, and again 10 to 12 months afterwards. After an average follow-up of about four years, 1,087 people died.Physical activity has long been linked to a lower risk of cardiovascular disease and premature death after events like a heart attack or stroke.The current study, however, offers fresh evidence of the potential to improve survival odds by exercising after a heart attack, or by trying to keep up with some workouts even if a previous level of exercise is difficult to maintain.“If you have not been active before your (heart attack), don’t worry, start now, it will improve your health and prognosis,” lead study author Orjan Ekblom of the Swedish School of Sport and Health Sciences in Stockholm said by e-mail. “If you have been active before your (heart attack) great, but keep it up.”“For individuals who cannot exercise it is important to underline that exercise is only a limited part of physical activity,” Ekblom advised. Just moving more around the home, or taking slow walks, can help, along with other things like reducing stress and avoiding alcohol and tobacco.It’s possible that exercise benefits people after a heart attack in many of the same ways it does before, said Claude Bouchard of the Pennington Biomedical Research Centre in Baton Rouge, Louisiana.Among other things, exercise might help improve risk factors for cardiovascular disease like obesity, high blood pressure, elevated blood sugar, high cholesterol, excess liver fat, and chronic inflammation, Bouchard, who wasn’t involved in the study, said by e-mail.Like other people, heart attack survivors should aim for about 150 minutes a week of moderate intensity activity, Bouchard said.“Walking is the easiest form of activity to pursue this goal,” Bouchard advised. “It has a very low risk of injury and allows for easy quantification of the exercise dose.”The study wasn’t a controlled experiment designed to prove whether or how activity levels might directly influence mortality rates after a heart attack.Another limitation is that it only asked how many days each week people got at least 30 minutes of physical activity; this doesn’t help assess which types of exercise, or how much, might be ideal.“However, based on the available literature to date, it seems like even low levels of physical activity even below the current recommendations relate to improved survival,” said Trine Moholdt of the Norwegian University of Science and Technology.While patients should check with their physicians before starting a new exercise routine, it’s likely that there would be good options for people at almost any fitness level, Moholdt, who wasn’t involved in the study, said by e-mail.“Exercise is safe and being sedentary is far more dangerous,” Moholdt said.